Magnesium Oxide-Induced Hypermagnesemia in a Patient with Renal Insufficiency

Hypermagnesemia is a rare laboratory finding, and life-threatening hypermagnesemia is even further rare; although it is reversible with early detection and treatment. Clinical hypermagnesemia usually results from excess exogenous magnesium intake in patients with severe renal failure or overdose infusion of magnesium salt in the cases of eclampsia and cardiac arrhythmias. Here, we present a case of hypermagnesemia, that had first been misdiagnosed as sepsis, presenting with coma, respiratory failure, hypotension, sinus bradycardia, areflexia, and hypothermia. This patient suffered from chronic constipation with regular use of magnesium oxide as laxative. In spite of mild renal insufficiency (Serum creatinine 2.0 mg/dl), hypermagnesemia of 11.2 mg/dl developed under the administration of magnesium oxide 250 mg per dose three times a day. Hemodialysis was performed due to severe symptomatic hypermagnesemia resistant to aggressive calcium gluconate, saline, and furosemide administration. His symptoms induced by hypermagnesemia subsided after hemodialysis. Accordingly, we suggest precautious use of magnesium of usual dose to treat constipation even in patients with mild renal insufficiency. We propose emergent hemodialysis may be life-saving in this clincial setting.